Scalpels are a class of knives used in the surgical environment for incising, stabbing, shaving, and curetting of human and animal tissue. Conventional scalpels used for this purpose have a stationary blade. The blade is always exposed thereby creating a hazard of inadvertent puncture to an operating team member and to any other person who may come in contact with an instrument. The primary hazard of puncture is the possible transmission of an infectious agent, such as the AIDS virus. It has long been a desire of the medical profession to provide a protective scalpel which completely and absolutely encircles and protects the blade during non-use.
In some emergency situations, a surgeon must work quickly and hand instruments back and forth to assistants. It is dangerous sometimes because the sharp scalpels can accidentally cut or jab the personnel's hands during the operation. Certain fatal infections can be transferred to individuals through small cuts.
Presently existing protective scalpels have removable guards to prevent contact with the blade during non-use. However, with the rapidity in which surgery is conducted, this imposes a degree of inconvenience which would be burdensome. Other conventional protective scalpels include examples in which a blade sheath pivots or extends and retracts upon a given force applied to a handle of the scalpel. These scalpels do not provide absolute security of the blade such as the present invention where the blade is completely encased in a sheath.
Prior art tool retraction/latch mechanisms have the disadvantage of exposed screws, springs, fasteners, gears, links, and the like which, upon certain conditions, could loosen and fall into a wound or cavity.
Another disadvantage of many protective scalpels is the encroachment of a portion of the scalpel blade. This interfaces with normal use of the scalpel, as entire length of the blade is typically used.
Examples of known prior art are:
U.S. Pat. No. 3,657,812 which discloses a retractable tool holder; PA1 U.S. Pat. No. 5,071,426 which discloses a surgical scalpel with a retractable blade guard; PA1 U.S. Pat. No. 5,116,351 which discloses a safety scalpel having a blade protecting sheath; PA1 U.S. Pat. No. 5,139,507 which discloses a surgical scalpel with a retractable blade guard; and PA1 U.S. Pat. No. 5,141,517 which discloses a retractable instrument automatically actuating the instrument to extend forward from a protective sheath.
The present invention solves many of the problems associated with prior art scalpels and latch mechanisms.